117: Impact of Drying on Functionality of Dough Made From Black Soldier Fly (Hermetia Illucens) Larvae (BSFL) Flours

Introduction

The increasing demand for sustainable and nutritionally rich food sources has spotlighted BSFL (Hermetia illucens) as a viable alternative to traditional proteins. However, the ability of BSFL flours to form doughs with desirable rheological characteristics is highly dependent on processing conditions, particularly drying. Drying is a thermal treatment applied along with scalding to ensure the microbiological safety of the flour. Thus, understanding the effect of drying on BSFL flour functionality is critical for expanding its applications in food systems. Rheological properties of doughs are key to their texture and handling characteristics to develop new fortified products.

Methods

Frozen BSFL (30 g) were scalded in boiling water for 8 minutes using a vessel equipped with a perforated sieving basket. After scalding, an average of 254±23 g of larvae was dried at 32°C, 40°C, or 50°C for 6, 8, and 22 hours, respectively, in a hot air convection dryer (Model UOP8-G, Armfield) with a 1.52 m/s airspeed. Ambient air was controlled at 32.1±0.1°C and 22.7±1.2% relative humidity (RH), while drying air RH was adjusted to 13%, 20%, or 25% based on the drying temperature. After drying, the samples were cooled to room temperature in a desiccator and ground and mixed with all-purpose flour in a 50:50 ratio to form doughs, with 100% all-purpose flour dough serving as a control. A TA DHR20 rheometer equipped with a 20mm serrated plate was used to run frequency sweep (0.1-100Hz) and creep-recovery tests (100 Pa, 180 sec) at 22°C in triplicate.

Results

All doughs showed increased elastic (G’) and viscous (G’’ ) moduli with frequency, with elastic modulus (G’) consistently higher (p<0.05). Higher drying temperatures yielded stiffer doughs with elevated G’ and G’’ values (p < 0.05), indicating stronger elastic properties. All dried BSFL doughs exhibited greater stiffness (G’) with higher creep recovery compared to the control.

Significance

The results suggest that optimization of drying conditions (temperature) is essential to ensure desirable dough functionality, including appropriate elasticity, viscosity, and stiffness. This study contributes to the efficient utilization of BSFL flours as sustainable, functional ingredients in food products, addressing global challenges of food security and environmental sustainability.

Authors: Roja Balupati, Rosana G. Moreira, M.E. Castell-Perez